x86, intel_txt: Intel TXT boot support

This patch adds kernel configuration and boot support for Intel Trusted
Execution Technology (Intel TXT).

Intel's technology for safer computing, Intel Trusted Execution
Technology (Intel TXT), defines platform-level enhancements that
provide the building blocks for creating trusted platforms.

Intel TXT was formerly known by the code name LaGrande Technology (LT).

Intel TXT in Brief:
o  Provides dynamic root of trust for measurement (DRTM)
o  Data protection in case of improper shutdown
o  Measurement and verification of launched environment

Intel TXT is part of the vPro(TM) brand and is also available some
non-vPro systems.  It is currently available on desktop systems based on
the Q35, X38, Q45, and Q43 Express chipsets (e.g. Dell Optiplex 755, HP
dc7800, etc.) and mobile systems based on the GM45, PM45, and GS45
Express chipsets.

For more information, see http://www.intel.com/technology/security/.
This site also has a link to the Intel TXT MLE Developers Manual, which
has been updated for the new released platforms.

A much more complete description of how these patches support TXT, how to
configure a system for it, etc. is in the Documentation/intel_txt.txt file
in this patch.

This patch provides the TXT support routines for complete functionality,
documentation for TXT support and for the changes to the boot_params structure,
and boot detection of a TXT launch.  Attempts to shutdown (reboot, Sx) the system
will result in platform resets; subsequent patches will support these shutdown modes
properly.

 Documentation/intel_txt.txt      |  210 +++++++++++++++++++++
 Documentation/x86/zero-page.txt  |    1
 arch/x86/include/asm/bootparam.h |    3
 arch/x86/include/asm/fixmap.h    |    3
 arch/x86/include/asm/tboot.h     |  197 ++++++++++++++++++++
 arch/x86/kernel/Makefile         |    1
 arch/x86/kernel/setup.c          |    4
 arch/x86/kernel/tboot.c          |  379 +++++++++++++++++++++++++++++++++++++++
 security/Kconfig                 |   30 +++
 9 files changed, 827 insertions(+), 1 deletion(-)

Signed-off-by: Joseph Cihula <joseph.cihula@intel.com>
Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: Gang Wei <gang.wei@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 379 insertions, 0 deletions

diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
new file mode 100644
index 000000000000..263591afd29e
--- /dev/null
+++ b/arch/x86/kernel/tboot.c
@@ -0,0 +1,379 @@
+/*
+ * tboot.c: main implementation of helper functions used by kernel for
+ *          runtime support of Intel(R) Trusted Execution Technology
+ *
+ * Copyright (c) 2006-2009, Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <linux/dma_remapping.h>
+#include <linux/init_task.h>
+#include <linux/spinlock.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/dmar.h>
+#include <linux/pfn.h>
+#include <linux/mm.h>
+
+#include <asm/trampoline.h>
+#include <asm/processor.h>
+#include <asm/bootparam.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/setup.h>
+#include <asm/tboot.h>
+#include <asm/e820.h>
+#include <asm/io.h>
+
+#include "acpi/realmode/wakeup.h"
+
+/* Global pointer to shared data; NULL means no measured launch. */
+struct tboot *tboot __read_mostly;
+
+/* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
+#define AP_WAIT_TIMEOUT         1
+
+#undef pr_fmt
+#define pr_fmt(fmt)     "tboot: " fmt
+
+static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
+
+void __init tboot_probe(void)
+{
+        /* Look for valid page-aligned address for shared page. */
+        if (!boot_params.tboot_addr)
+                return;
+        /*
+         * also verify that it is mapped as we expect it before calling
+         * set_fixmap(), to reduce chance of garbage value causing crash
+         */
+        if (!e820_any_mapped(boot_params.tboot_addr,
+                             boot_params.tboot_addr, E820_RESERVED)) {
+                pr_warning("non-0 tboot_addr but it is not of type E820_RESERVED\n");
+                return;
+        }
+
+        /* only a natively booted kernel should be using TXT */
+        if (paravirt_enabled()) {
+                pr_warning("non-0 tboot_addr but pv_ops is enabled\n");
+                return;
+        }
+
+        /* Map and check for tboot UUID. */
+        set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
+        tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
+        if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
+                pr_warning("tboot at 0x%llx is invalid\n",
+                           boot_params.tboot_addr);
+                tboot = NULL;
+                return;
+        }
+        if (tboot->version < 5) {
+                pr_warning("tboot version is invalid: %u\n", tboot->version);
+                tboot = NULL;
+                return;
+        }
+
+        pr_info("found shared page at phys addr 0x%llx:\n",
+                boot_params.tboot_addr);
+        pr_debug("version: %d\n", tboot->version);
+        pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
+        pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
+        pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
+        pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
+}
+
+static pgd_t *tboot_pg_dir;
+static struct mm_struct tboot_mm = {
+        .mm_rb          = RB_ROOT,
+        .pgd            = swapper_pg_dir,
+        .mm_users       = ATOMIC_INIT(2),
+        .mm_count       = ATOMIC_INIT(1),
+        .mmap_sem       = __RWSEM_INITIALIZER(init_mm.mmap_sem),
+        .page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
+        .mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
+        .cpu_vm_mask    = CPU_MASK_ALL,
+};
+
+static inline void switch_to_tboot_pt(void)
+{
+        write_cr3(virt_to_phys(tboot_pg_dir));
+}
+
+static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
+                          pgprot_t prot)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd;
+        pte_t *pte;
+
+        pgd = pgd_offset(&tboot_mm, vaddr);
+        pud = pud_alloc(&tboot_mm, pgd, vaddr);
+        if (!pud)
+                return -1;
+        pmd = pmd_alloc(&tboot_mm, pud, vaddr);
+        if (!pmd)
+                return -1;
+        pte = pte_alloc_map(&tboot_mm, pmd, vaddr);
+        if (!pte)
+                return -1;
+        set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
+        pte_unmap(pte);
+        return 0;
+}
+
+static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
+                           unsigned long nr)
+{
+        /* Reuse the original kernel mapping */
+        tboot_pg_dir = pgd_alloc(&tboot_mm);
+        if (!tboot_pg_dir)
+                return -1;
+
+        for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
+                if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
+                        return -1;
+        }
+
+        return 0;
+}
+
+void tboot_create_trampoline(void)
+{
+        u32 map_base, map_size;
+
+        if (!tboot_enabled())
+                return;
+
+        /* Create identity map for tboot shutdown code. */
+        map_base = PFN_DOWN(tboot->tboot_base);
+        map_size = PFN_UP(tboot->tboot_size);
+        if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
+                panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n", map_base, map_size);
+}
+
+static void set_mac_regions(void)
+{
+        tboot->num_mac_regions = 3;
+        /* S3 resume code */
+        tboot->mac_regions[0].start = PFN_PHYS(PFN_DOWN(acpi_wakeup_address));
+        tboot->mac_regions[0].size = PFN_UP(WAKEUP_SIZE) << PAGE_SHIFT;
+        /* AP trampoline code */
+        tboot->mac_regions[1].start =
+                        PFN_PHYS(PFN_DOWN(virt_to_phys(trampoline_base)));
+        tboot->mac_regions[1].size = PFN_UP(TRAMPOLINE_SIZE) << PAGE_SHIFT;
+        /* kernel code + data + bss */
+        tboot->mac_regions[2].start = PFN_PHYS(PFN_DOWN(virt_to_phys(&_text)));
+        tboot->mac_regions[2].size = PFN_PHYS(PFN_UP(virt_to_phys(&_end))) -
+                                     PFN_PHYS(PFN_DOWN(virt_to_phys(&_text)));
+}
+
+void tboot_shutdown(u32 shutdown_type)
+{
+        void (*shutdown)(void);
+
+        if (!tboot_enabled())
+                return;
+
+        /*
+         * if we're being called before the 1:1 mapping is set up then just
+         * return and let the normal shutdown happen; this should only be
+         * due to very early panic()
+         */
+        if (!tboot_pg_dir)
+                return;
+
+        /* if this is S3 then set regions to MAC */
+        if (shutdown_type == TB_SHUTDOWN_S3)
+                set_mac_regions();
+
+        tboot->shutdown_type = shutdown_type;
+
+        switch_to_tboot_pt();
+
+        shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
+        shutdown();
+
+        /* should not reach here */
+        while (1)
+                halt();
+}
+
+static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
+{
+#define TB_COPY_GAS(tbg, g)                     \
+        tbg.space_id     = g.space_id;          \
+        tbg.bit_width    = g.bit_width;         \
+        tbg.bit_offset   = g.bit_offset;        \
+        tbg.access_width = g.access_width;      \
+        tbg.address      = g.address;
+
+        TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
+        TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
+        TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
+        TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
+
+        /*
+         * We need phys addr of waking vector, but can't use virt_to_phys() on
+         * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
+         * addr.
+         */
+        tboot->acpi_sinfo.wakeup_vector = fadt->facs +
+                offsetof(struct acpi_table_facs, firmware_waking_vector);
+}
+
+void tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
+{
+        static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
+                /* S0,1,2: */ -1, -1, -1,
+                /* S3: */ TB_SHUTDOWN_S3,
+                /* S4: */ TB_SHUTDOWN_S4,
+                /* S5: */ TB_SHUTDOWN_S5 };
+
+        if (!tboot_enabled())
+                return;
+
+        tboot_copy_fadt(&acpi_gbl_FADT);
+        tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
+        tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
+        /* we always use the 32b wakeup vector */
+        tboot->acpi_sinfo.vector_width = 32;
+        tboot->acpi_sinfo.kernel_s3_resume_vector = acpi_wakeup_address;
+
+        if (sleep_state >= ACPI_S_STATE_COUNT ||
+            acpi_shutdown_map[sleep_state] == -1) {
+                pr_warning("unsupported sleep state 0x%x\n", sleep_state);
+                return;
+        }
+
+        tboot_shutdown(acpi_shutdown_map[sleep_state]);
+}
+
+int tboot_wait_for_aps(int num_aps)
+{
+        unsigned long timeout;
+
+        if (!tboot_enabled())
+                return 0;
+
+        timeout = jiffies + AP_WAIT_TIMEOUT*HZ;
+        while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
+               time_before(jiffies, timeout))
+                cpu_relax();
+
+        return time_before(jiffies, timeout) ? 0 : 1;
+}
+
+/*
+ * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
+ */
+
+#define TXT_PUB_CONFIG_REGS_BASE       0xfed30000
+#define TXT_PRIV_CONFIG_REGS_BASE      0xfed20000
+
+/* # pages for each config regs space - used by fixmap */
+#define NR_TXT_CONFIG_PAGES     ((TXT_PUB_CONFIG_REGS_BASE -                \
+                                  TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
+
+/* offsets from pub/priv config space */
+#define TXTCR_HEAP_BASE             0x0300
+#define TXTCR_HEAP_SIZE             0x0308
+
+#define SHA1_SIZE      20
+
+struct sha1_hash {
+        u8 hash[SHA1_SIZE];
+};
+
+struct sinit_mle_data {
+        u32               version;             /* currently 6 */
+        struct sha1_hash  bios_acm_id;
+        u32               edx_senter_flags;
+        u64               mseg_valid;
+        struct sha1_hash  sinit_hash;
+        struct sha1_hash  mle_hash;
+        struct sha1_hash  stm_hash;
+        struct sha1_hash  lcp_policy_hash;
+        u32               lcp_policy_control;
+        u32               rlp_wakeup_addr;
+        u32               reserved;
+        u32               num_mdrs;
+        u32               mdrs_off;
+        u32               num_vtd_dmars;
+        u32               vtd_dmars_off;
+} __packed;
+
+struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
+{
+        void *heap_base, *heap_ptr, *config;
+
+        if (!tboot_enabled())
+                return dmar_tbl;
+
+        /*
+         * ACPI tables may not be DMA protected by tboot, so use DMAR copy
+         * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
+         */
+
+        /* map config space in order to get heap addr */
+        config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
+                         PAGE_SIZE);
+        if (!config)
+                return NULL;
+
+        /* now map TXT heap */
+        heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
+                            *(u64 *)(config + TXTCR_HEAP_SIZE));
+        iounmap(config);
+        if (!heap_base)
+                return NULL;
+
+        /* walk heap to SinitMleData */
+        /* skip BiosData */
+        heap_ptr = heap_base + *(u64 *)heap_base;
+        /* skip OsMleData */
+        heap_ptr += *(u64 *)heap_ptr;
+        /* skip OsSinitData */
+        heap_ptr += *(u64 *)heap_ptr;
+        /* now points to SinitMleDataSize; set to SinitMleData */
+        heap_ptr += sizeof(u64);
+        /* get addr of DMAR table */
+        dmar_tbl = (struct acpi_table_header *)(heap_ptr +
+                   ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
+                   sizeof(u64));
+
+        /* don't unmap heap because dmar.c needs access to this */
+
+        return dmar_tbl;
+}
+
+int tboot_force_iommu(void)
+{
+        if (!tboot_enabled())
+                return 0;
+
+        if (no_iommu || swiotlb || dmar_disabled)
+                pr_warning("Forcing Intel-IOMMU to enabled\n");
+
+        dmar_disabled = 0;
+#ifdef CONFIG_SWIOTLB
+        swiotlb = 0;
+#endif
+        no_iommu = 0;
+
+        return 1;
+}